Recently, various flat panel displays have been developed. Particularly, an organic EL (ElectroLuminescence) display device has gained a great deal of attention as an excellent flat panel display because it can realize low power consumption, reduction in thickness, and high definition.
However, since the organic EL display device has a high external-light reflectance, it has a problem of reducing its contrast when used near a window or outdoors.
How the organic EL display device carries out full-color display is classified into, for example, two large methods. That is, the organic EL display device carries out full-color display by use of (i) an EL layer which emits red light, green light, and blue light (selective application method) or (ii) an EL layer which emits white light, a color filter which transmits red light, a color filter which transmits green light, and a color filter which transmits blue light.
In a field of the organic EL display device, particularly, various structures which realize high contrast have been studied.
Patent Literature 1 discloses a light-emission type organic EL display panel (see FIG. 11) in which (i) a transparent first support 111, a first electrode 120, an organic EL layer 140, a second electrode 125, and a second support 112 are laminated in this order and (ii) an insulating layer 130 is provided between the first electrode 120 and the second electrode 125 so as not to cover a luminescent region but so as to cover a non-luminescent region. The light-emission type organic EL display panel emits light outwards via the first support 111.
The light-emission type organic EL display panel further includes a visibility suppression layer 170 which suppresses visibility caused due to difference in reflectance or difference in color tone between (i) at least one of the second electrode 125, an auxiliary electrode 127, and the organic EL layer 140 and (ii) a surrounding of the at least one of the second electrode 125, the auxiliary electrode 127, and the organic EL layer 140.
Patent Literature 1 describes that, with such a configuration, it is possible to suppress unnecessary visibility caused due to difference in reflectance or difference in color tone between (i) at least one of the second electrode 125, the auxiliary electrode 127, and the organic EL layer 140 and (ii) the surrounding of the at least one of the second electrode 125, the auxiliary electrode 127, and the organic EL layer 140.
Patent Literature 2 discloses a display device in which a light absorbing layer is provided on an insulating film between open parts each of which serves as a light emitting section. With the configuration, the display device can prevent contrast from being deteriorated due to reflection of external light.
Patent Literature 3 discloses an organic EL device which includes a metal electrode and an elliptical polarizing plate that can polarize visible light having a broadband wavelength region. With the configuration, the organic EL device can prevent external light having the broadband wavelength region from being reflected by the metal electrode.